The present disclosure relates to the subject matter disclosed in German application No. 101 62 861.7 of Dec. 12, 2001, which is incorporated herein by reference in its entirety and for all purposes.
The invention relates to a lever clamp comprising a slide rail, a fixed jaw, which is arranged on the slide rail, and a slide arm, which can be displaced on the slide rail and on which a lever element is mounted in a pivotable manner and a pressure plate is mounted such that it can be displaced transversely to the slide arm, it being possible for the movement of the pressure plate towards the fixed arm to be actuated by a pivoting movement of the lever element, so that a workpiece can be clamped between the fixed arm and pressure plate.
Such lever clamps are known by the designation GH or GSH from Bessey and Sohn GmbH and Co.
Such lever clamps can be used for clamping in workpieces by means of leverages. They can be used advantageously, in particular, when a large number of clamps have to be set in place and released in a time-saving manner. It is possible then for high clamping forces to be achieved quickly, with only a low level of force being applied, via the corresponding lever element.
In accordance with the present invention, a lever clamp which is straightforward and cost-effective to manufacture is provided.
In accordance with the invention, in order to form a pivot bearing for the pivotability between the lever element and slide arm, a pivoting-shaft element is arranged on the lever element, or the slide arm and the slide arm or the lever element has a pivoting-shaft mount, in which the pivoting-shaft element can be positioned and by means of which the pivoting-shaft element and pivoting-shaft mount can be rotated relative to one another.
Since a pivoting-shaft element is arranged on the lever element or the slide jaw and a pivoting-shaft mount, in which the pivoting-shaft element can be positioned, is provided on the corresponding other part, that is to say the slide arm or the lever element, respectively, it is possible to minimize the number of components for assembling a corresponding lever clamp. Furthermore, there is no need to provide, in particular, any positive-locking elements in order to form a corresponding pivot bearing. This also simplifies the assembly. In addition, the lever element may be manufactured from a plastics material, it being possible for the pivoting-shaft element to be produced integrally. This, in turn, minimizes the weight of such a lever clamp.
In particular, the pivoting-shaft element is arranged in a rotationally fixed manner on the lever element or the slide arm, so that, if the pivoting element is arranged on the lever element, the pivoting-shaft element can be rotated in the corresponding pivoting-shaft mount during pivoting of the lever or, if the pivoting-shaft element is arranged on the slide arm, the pivoting-shaft mount of the lever element can be rotated about the pivoting-shaft element on the slide arm. This realizes a pivot bearing which can easily be assembled and in the case of which the number of components required is minimized.
It may be provided, in principle, that the pivoting-shaft element is a separate component which is fixed correspondingly on the lever element or on the slide arm. It is quite particularly advantageous, however, if the pivoting-shaft element is formed integrally or in a one-piece arrangement on the lever element or on the slide arm. In this case, it is produced integrally with the lever element or the slide arm and the number of components is minimized as a result. The amount of time required for assembling a corresponding lever clamp is also minimized.
It may also be provided that the pivoting-shaft element is arranged in a force-locking manner on the lever element or the slide arm by, for example, a corresponding cylindrical pin being pushed into mounts provided for this purpose, in which case rotatability about this pin, or of this pin, is ensured.
It is quite particularly advantageous if the pivoting-shaft mount is formed as a recess on a surface of the slide arm or of the lever element, said recess being directed toward the fixed arm. Such an open recess, for example a half-open bore, is straightforward to produce and, in particular, can be produced integrally during the production of the slide arm or of the lever element. The assembly and, in particular, the joining together of the lever element and slide arm in order to form the pivot bearing may be simplified in that the pivoting-shaft element can be positioned in the corresponding pivoting-shaft mount, although there is no need to provide any specific positive-locking elements.
It is quite particularly advantageous if the lever element has a recess by means of which the lever element can be positioned on the slide arm such that it surrounds the latter at least partially. A corresponding lever clamp according to the invention can thus be manufactured straightforwardly and cost-effectively. On the one hand, the number of components required is minimized and, on the other hand, the lever clamp according to the invention can easily be assembled since, in particular, no screws or bolts or the like are required.
Furthermore, it is particularly advantageous if accommodating stubs are arranged on opposite surfaces of the lever element. By means of these accommodating stubs, in turn, it is possible to form a guide for a pivoting/translatory movement of the pressure plate. This, in turn, minimizes the number of components and the lever clamp according to the invention can be assembled straightforwardly and cost-effectively. Furthermore, it is thus possible to provide an inner surface for retaining a pivoting-shaft element in a force-locking manner.
In particular, an accommodating stub projects beyond a surface of the lever element in order for it to be possible for it to enter (plunge) into a guide of a pressure plate.
Furthermore, it is advantageous if the lever element and the slide arm are adapted to each other such that the pivoting-shaft element is blocked from moving in a translatory manner out of the pivoting-shaft mount. If the mount is formed as a recess in a surface, then the lever element is basically not blocked from moving away from the slide arm. The corresponding formation of the lever element and slide arm in coordination with one another, however, makes it possible to achieve such a blocking action, it nevertheless being possible for the slide arm to be manufactured, in particular, without any high-outlay milling.
For example, the lever element is provided with a first blocking element and the slide arm is provided with a corresponding second blocking element, the lever element being blocked from moving away from the slide arm by the first blocking element striking against the second blocking element. It may thus be provided that a pin element projects, or mutually opposite pin elements project, into a corresponding recess of the lever element and the slide arm is provided with a beaded rim, the lever element and slide arm being blocked from moving away from one another by the pin elements butting against the beaded rim.
In order to subject a workpiece to a compressive force, it is provided that a distance between an activating surface, by means of which the lever element acts on the pressure plate, and a surface of the slide arm which is located opposite the fixed arm depends on the pivoting angle of the lever element. This can be achieved by the formation of a corresponding eccentric surface. A workpiece may then be subjected to a compressive force via a torque exerted by means of the lever element.
It is provided, in particular, that the activating surface is closed, i.e. is continuous. The contact region by means of which said surface acts on the pressure plate is thus increased in size. Consequently, in turn, the force to which the pressure plate is subjected is distributed over a greater surface area; analogously, the same applies to the opposing forces to which the lever element is subjected by the pressure plate.
A clamping movement which is induced by the lever element and by which a workpiece is subjected to a compressive force can easily be achieved in that the pressure plate surrounds the lever element at least partially. It is thus possible for an accommodating stub on the lever element to be formed as a guide element for the pressure plate.
In particular, the pressure plate is then guided such that it can be displaced in a pivotable manner on the accommodating stub. The workpiece may be subjected to a compressive force via the displaceability which is induced by the lever element. Since a pivoting movement of the lever element has to be converted into a linear movement, and this takes place via an eccentric, the pivoting mounting ensures that the pressure plate, irrespective of the pivoting position of the lever element, is aligned in relation to the workpiece surface.
It is quite particularly advantageous if arranged in a pivotable manner on the lever element is a locking latch by means of which it is possible to block the pivotability of the lever element on the slide arm in one direction, and blocking can be released by pivoting the locking latch counter to the blocking direction, the locking latch being supported on the lever element via a spring element formed on it, and the spring element forcing the locking latch in the blocking direction.
The locking latch makes it possible to prevent release of a clamping position. Provided the locking latch is not released, the lever element can then only be moved in one direction, namely in the clamping direction. The spring element, which forces corresponding tooth elements of the locking latch automatically into a toothing formation of the slide arm, prevents the lever element from springing back. It is nevertheless possible for this clamping position to be easily released by pivoting the locking latch counter to the blocking direction, in order thus correspondingly to disengage the tooth elements from the toothing formation.
The locking latch with spring element is formed, in particular, in one piece, so that, in turn, the number of components is minimized and the locking latch can easily be fitted on the lever element. There is no need, in particular, for any separate spring element, for example a helical spring, in order to achieve the blocking action.
It is further advantageous in design terms if a pivoting shaft of the locking latch on the lever element is formed by stub elements. It is possible for these to be formed integrally on the locking latch and thus to be manufactured integrally.
Furthermore, it is advantageous if the lever element has a push-in guide for the stub elements of the locking latch, so that the stub elements can be latched in stub mounts of the lever element in order to form a pivot bearing. The corresponding pivot bearing is thus straightforward to produce without, for example, additional tools being required. If the stub elements have been latched into the stub mounts, then the locking pawl is retained in a secure and pivotable manner on the lever element. This latching-in operation is correspondingly facilitated by the push-in guide.
It is provided that the slide arm is provided with a toothing formation, it being possible for one or more tooth elements of the locking latch to be brought into engagement with the toothing formation in order to block the pivoting movement of the lever element. This allows a clamping position to be secured, it being possible, starting from such a clamping position, to ensure, for example, that it is only possible to increase the compressive force to which a workpiece is subjected, but the clamping position cannot be released; for release purposes, the locking latch has to be pivoted in relation to the lever element.
A slide arm can be manufactured cost-effectively by diecasting or injection molding. It is possible for a toothing formation to be integrally formed and likewise for a recess to be manufactured integrally as pivoting-shaft mount. There is then no longer any need for any subsequent milling processes.
The lever clamp according to the invention is straightforward and cost-effective to produce if the lever element is produced from a plastics material. The pressure plate can also be produced from a plastics material. Furthermore, the locking latch can be manufactured from a plastics material. It is also possible for the weight of a lever clamp to be minimized correspondingly.
It is possible to secure a clamping position of a workpiece between the fixed arm and the slide arm of the clamp in that the slide arm can be tilted in relation to the slide rail. The slide arm is thus secured against moving away from the workpiece in a translatory manner on the slide rail.
In particular, the lever clamp according to the invention consists of the slide rail, the fixed arm, the slide arm, the lever element, the pressure plate and a locking latch for blocking the pivotability of the lever element. A lever clamp can be assembled from a minimal number of components, it being possible, in turn, for the assembly to be easily carried out without, for example, special tools being required.
The following description of a preferred embodiment is used, in conjunction with the drawing, in order to explain the invention in more detail.